Air filter



OC. 27, 1931.. M, 5:f DURREN 1,829,344

AIR FT'LTER n Filed Sept. 19. 1930 A TTORNEY.

Patented Get. 27, 193

" UNrrED STATES MERLE I. DURREN, F IDOWAGIAC, MICHIGAN AIR FILTER Application filed September 19, 1930. Serial No. 482,973.

The invention relates to air'filters, and particularly to air lters for use in hot air furnaces, and has for its object to provide a device o f this character adapted to be positioned within th-e casing of the furnace whereby all of the air-passing through said furnace will be filteredwithout retarding the circulation of air through the furnace.

'A further object is to provide a device of A.this character formed of filtering material whose area is large in proportion to the cross sectional area of the air `intakes of the furnace.

A further object is to provide a device of @this character formed of a plurality of sections adapted to be easily inserted in the furnace casingand adapted to be secured t0- gether in the casing in contacting relation to form a filtering unit.

A'further object is to provide a device of this character of a shape conforming to the inner periphery of the furnace casing adapted to -be mounted upon the floor of the furnace in spaced relation to the casing and eX- tending into engagement with the inner periphery of the casing above the furnace air ducts whereby said device provides a passageway about the inner periphery of the furnace communicating with said air ducts.

vWith the above and other objects in view, the invention resides in the combination and arrangement of parts as hereinafter set forth, shown in the drawing, described and claimed, it being understood that changes in the precise embodiment of the invention may be made within the scope of what is claimed without departing from the spirit of the in vention.

In the drawings:

Figure 1 is a view in front elevation and Y partly in section of a furnace provided with viewv lof furnace having subsurface air ducts and provided with the filtering device.

Referring to the drawings, which illustrates the preferred embodiment of the invention, the numeral designates a conventional hot air furnace having a casing 11, a fire box 12, a smoke flue 13, heating pipes 14, ash chamber 15, and air ducts 16. My filtering device 17 is adapted to be mounted in the casing 12 of the furnace at the lower end thereof and adjacent the air ducts 16, so that the air entering the furnace casing through said ducts must pass through said filtering device in entering said casing.l The filtering device is formed in a plurality of sections 18 of a shape conformingto the inner periphery of the casing and preferably of the same size and shape, which are adapted to be secured together in end-contacting relation to form a filtering unit. As best illustrated in transverse section in Figure 1, each section 18 is formed of a vertically eX- tending portion 19 mounted on the floor ofV the furnace in spaced relation to the inner periphery of the casing', and an angularly outwardly extending portion 2O integrally formed with portion 19 and terminating in a; short upwardly extending. portion 21 engaging the inner periphery of the casing above the point at which the air ducts enter the casing.

The filtering device is preferably formed of spaced inner and outer wire screens 22 having interposed between them a suitable filtering element 28, such as steel wool, although it is to be understood that any other ltering element may be used; The upper and lower edges of each section of the device are bound by channel-sectioned members 24 and 25, respectively,- which are preferably formed of sheet metal and which serve to hold the screens 22 and the filtering element 23 in their correct position in the device. The ends of each section are also bound by end members 26of channel-section and of a shape conforming to the sectional shape of the filtering member, as described. Each section 18 thus has its peripheral edges suitably bound by members 24, and 26, which Gil members also reinforce the sections andfhold them in their proper shape.

Vt herearound Within the inner periphery thereof, and said sections are secured together in proper relation by any suitable means suchA f as vvires'27 Wound around the contactingend members 26 of adjacent sections 18 of the device, and said sections thus form a continu-v.

ous device ofthe sameshape and'section throughout. The ends of the filtering device when assembled preferably extend to the lopposite sides ofthe, ash chamber l5, and these ends are provided With suitable caps 28illustrated in Figure 4,'Which'comy prise a plate carri'ed'by the end of the filter-y ingrmember and extendingperpendicularly therefrom; tothe fioor land casing of the furnace.l i.

It will thusbe seen that the filtering element is disposed in the furnace casing tol form l' a passage-Way formed of filtering material and conforming to the shape of the casing ywhich extends about "the inner periphery of the casing at its lower end and communicates with the air ducts of the furnace. The passagevvay'so vformed'has its ends closed by the plates 2S`Whereby allofthe air entering the V'furnace casing must pass through theffiltering element, although it may travel through said passage-Way and thence pass .through the iiltering'-device at a'point remote from the'air duct in entering the furnace casing proper. VThe filtering element, beingofan area many times larger than the cross sectional area of the air ducts communicating With the casing, does not retard the circulationfof air infthe' heating system as do filters lof anrarea. only equal to the cross sectional area ofthe air duct. Therefore when used in connection with gravity-operated air circulating systems the filter does not retard the circulation of the system, and When used vin connection 'With a forced air circulation vsystem they air is properly filtered and is not forced through the filter under a high pres-- sure Which'destroys the filteringk action` of a filter. It is also obvious'that this device as constructed iny sections may be installed in a furnace duringitserection, or'inay be installed in a previously erected furnace,'With substantially equal facility. j

The device as lillustrated in Figures l to 4 Ais shown as applied to a vfurnace of the "type,Y in 'which the coldair ducts are positioned above the surface of the floor; and in Figure 5 the device is illustrated in connection with` 29 inv the floor communicates-With the afi-r i ducts, and the furnace casing ismounted Yabout'said pit.r With such furnaces the filtering v device YisV mounted rinthe pit to form the filtering passage-Way therein in the sameY manner as hereinbefore described.

It 1s contemplated that various changes may be made in the specificshape andassembly of the device, and in .the specific materials employed. Thus the endplates 28 be replaced by filtering membersy of the l* -device of a form substantially linear in cross section to extend angularly from the floor to the casingV rather than vertically from the floor and thence angularly tothe casing.

VThe invention having been set. forth, what is claimed as neW and useful is:

, l. The combination Witha hotairfurnace having a casing, anair duct communicating With said casing, of an air filter'mounted ink said casing, said airV filter cooperating With said casingto form a closed 'passage-Way in said casing communicating with said' air duct whereby the air from said duct passes through said passage-Way and lter in entering saidl casing.

2. Thercombination vvitha hot air furnace having a casing, an air duct Communicating With -said casing, of an air filter mounted in said casing, said air filter cooperating'vvith said casing tof-erm a passage-Way in said casing communicating with said air duct', means closing the ends of said passage-way- Whereby the air from saidductpass'es through said filter from said passage-Way in entering said casing. l ,Y

3. The combination With a hot air furnace having a yfioor,` a casing, 'an air duct com municating with said casing7 of an air filter mounted in said casing, said filter being mounted onthe furnace floor in spaced'relation to the casing and extending into engagement with the casing above the air duct to forma passage-Way communicating With the y' air duct', the air Vfrom said duct passing through said passage-Away and filter inentermeansclosing the ends of said passage-Wayv whereby the air from said duct passes through said passage-Way and filter in entering said casing. f

5. Thecombination With a hot air furnace having a casing, an air duct communicating l With said casing, of an air filter mounted in said casing, said air' filter cooperating with said casing to form a closed passage-Way in Y said casing communicating With said Vair duct, and reinforcing means carried by said filter and supporting it in passage-forming position.

6. The combination with a hot air furnace having a floor, a casing, an air duct communicating with said casing, of an air lter mounted in said casing to form a passageway communicating with said duct, said air filter comprising a lower upwardly extending portion mounted on the floor in spaced relation to the casing and terminating in an upper outwardly extending portion'engaging said casing above said air duct, the air from said air duct passing through said passageway and filter in entering said casing.

7. The combination with a hot air furnace having a floor, a casing, an air duct communicating with said casing, of an air filter mounted in said casing to form a passageway communicating with said duct, said air filter comprising a lower upwardly extending portion mounted on the door in spaced relation to the casing and terminating in an upper outwardly extending portion engaging said casing above said air duct, and means closing the ends of said passage-way whereby the air from said duc-t passes through said passage-way and filter in entering said casing.

8. The combination with a hot air furnace having a oor, a casing, an air duct communicating with said casing, of an air filter mounted in said casing, said lter comprising a lower upwardly extending portion mounted on said floor in spaced relation to said casing and terminating in an upper outwardly extending portion engaging said casing above said duct, plates carried by the ends of said filter and extending perpendicularly thereto into engagement with said floor and casing, and means carried by the upper and lower edges of said filter to support and position said filter in said casing.

9. The combination with a hot air furnace having a floor, a. casing, an air duct communicating with said casing, of an air filter formed in a plurality of sections, said filter being mounted on theV fioor of the furnace in spaced relation to the furnace casing and engaging the casing above said air duct to provide a passage-way communicating with said duct, means securing said filter sections together in end-contacting relation, and means closing the ends of said passage-way.

10. The combination with a hot air furnace having a floor, a casing, an air duct communicating with said casing, of an air filter formed in a plurality of sections, each of said sections comprising a lower upwardly extending portion mounted on the floor in spaced relation to the casing and terminating in an outwardly extending upper section engaging said casing, reinforcing means secured to the peripheral edges of each section of said lter, means for securing said filter sections together, and a plate carried by each end section at the outer end thereof and extending therefrom into engagement with said floor and casing.

11. The combination with a furnace having a combustion chamber and a spaced casing, an air duct communicating with said casing, of a filter forming an elongated passage-way in said casing communicating with said air duct, whereby air entering said passage-way from said duct and passing therethrough is distributed in a wide area between the combustion chamber and furnace casing.

l2. The combination with a furnace having a combustion chamber and a spaced casing, an air duct communicating with said casing, of a filter member disposed in said casing to form a passage-way extending substantially thereabout and communicating with said air duct, said filter being arranged to diffuse the air from said air duct throughout the casing.

In testimony whereof I affix my signature.

MERLE P. DURREN. 

